The SAGEX Review on Scattering Amplitudes, Chapter 8: Half BPS correlators

Abstract

Half BPS correlators in N = 4 super Yang-Mills theory are key quantities both in the AdS/CFT correspondence as well as in scattering amplitudes research. They are dual at strong coupling to quantum gravity amplitudes. At weak coupling on the other hand they contain all N = 4 SYM amplitudes. They have been found to possess a number of hidden symmetries, for example non-trivial permutation symmetry of perturbative four-point integrands and a higher dimensional conformal symmetry. Their study has enjoyed continuous progress since the discovery of AdS/CFT and they are now some of the best understood quantities of any four-dimensional quantum field theory.In this review we outline the current knowledge of half BPS correlators, emphasising these two co-existing relations to scattering amplitudes at strong and weak coupling.

The SAGEX review on scattering amplitudes Chapter 5: Analytic bootstraps for scattering amplitudes and beyond

“…Protected correlators, their connection to scattering amplitudes in N = 4 SYM, and related bootstrap approaches for computing them are also discussed in chapter 8[239] of the SAGEX review[42] 22. This is an instance of a more general folding procedure, which carries over from Dynkin diagrams to cluster algebras, and allows one to embed B n , C n , F 4 and G 2 inside A 2n−1 , D n+1 , E 6 and D 4 , respectively[102] 23.…”